Apparatus and method for handover signalling

Abstract

Control of handover of a User Equipment (UE) between a first base station of a first type and a second base station of a second, different type in a cellular network. At least one handover parameter is configured at one or more of: the UE; the first base station; and the second base station, on the basis of the first type and the second type.

What is claimed is: 
     
         1 . A method for controlling handover of a User Equipment (UE) between a first base station of a first type and a second base station of a second type in a cellular network, the method comprising:
 configuring at least one handover parameter at one or more of: the UE, the first base station, and the second base station, on the basis of the first type and the second type, wherein the first type and the second type are different.   
     
     
         2 . The method of  claim 1 , wherein the step of configuring the at least one handover parameter is further based on a contextual parameter of one or more of: the UE, the first base station, and the second base station. 
     
     
         3 . The method of  claim 1 , further comprising:
 determining to handover the UE between the first base station and the second base station based on the at least one handover parameter.   
     
     
         4 . The method of  claim 3 , wherein the step of determining comprises:
 comparing a first link quality and a second link quality using the at least one handover parameter, the first link quality relating to a link between the UE and the first base station and the second link quality relating to a link between the UE and the second base station.   
     
     
         5 . The method of  claim 1 , wherein the step of configuring the at least one handover parameter comprises:
 determining the at least one handover parameter on the basis of the first type and the second type; and   communicating the determined at least one handover parameter from the first base station or the second base station to the UE.   
     
     
         6 . The method of  claim 1 , wherein the step of configuring the at least one handover parameter comprises:
 adjusting the at least one handover parameter based on a handover performance characteristic, wherein the handover performance characteristic comprises at least one of: a number of successful handovers, a number of unsuccessful handovers, a rate of successful handovers, and a rate of unsuccessful handovers.   
     
     
         7 . The method of  claim 1 , wherein the first and second types relate to a capability of the base station to operate when mobile. 
     
     
         8 . The method of  claim 1 , wherein the at least one handover parameter comprises one or more of: an offset parameter indicative that a second link quality of the second base station exceeds a first link quality of the first base station, a hysteresis parameter, and a threshold parameter. 
     
     
         9 . The method of  claim 1 , further comprising:
 establishing one or both of: the first type and the second type on the basis of at least one of: a base station identifier for the first base station, a base station identifier of the second base station, and base station identifiers of the both respectively.   
     
     
         10 . The method of  claim 1 , further comprising:
 establishing one or both of: the first type, and the second type on the basis of at least one of: signalling from the first base station, signalling from the second base station, and signalling from the both respectively.   
     
     
         11 . The method of  claim 1 , further comprising:
 establishing one or both of: the first type and the second type by receiving data from a network management system.   
     
     
         12 . The method of  claim 1 , wherein the first base station is configured to operate when mobile, the method further comprising:
 determining that the first base station has a stationary state; and   effecting an update of the at least one handover parameter with respect to the first base station at one or both of: the UE and the second base station, in response to the determination of the stationary state.   
     
     
         13 . The method of  claim 12 , wherein the step of effecting an update comprises initiating a neighbour relations update at the first base station, wherein neighbour relations represent other base stations to which the UE can be handed over. 
     
     
         14 . The method of  claim 2 , wherein a contextual parameter is indicative of at least one of: a mobility state, a stationary state, a mobility parameter, at least one technology feature, a location, and traffic load. 
     
     
         15 . A non-transitory computer program readable medium comprising instructions that when executed cause a processor to perform a method for controlling handover of a User Equipment (UE) between a first base station of a first type and a second base station of a second type in a cellular network, the method comprising:
 configuring at least one handover parameter at one or more of: the UE, the first base station, and the second base station, on the basis of the first type and the second type, wherein the first type and the second type are different.   
     
     
         16 . A handover controller for managing handover of a User Equipment, UE, between a first base station of a first type and a second base station of a second type in a cellular network, the handover controller comprising:
 a configuration circuit, arranged to configure at least one handover parameter at one or more of: the UE, the first base station, and the second base station, on the basis of the first type and the second type, wherein the first type and the second type are different.   
     
     
         17 . A base station of a cellular network, comprising a handover controller for managing handover of a User Equipment, UE, between a first base station of a first type and a second base station of a second type in a cellular network, the handover controller comprising:
 a configuration circuit, arranged to configure at least one handover parameter at one or more of: the UE, the first base station, and the second base station, on the basis of the first type and the second type, wherein the first type and the second type are different.